NARRATOR: The metric system is a way of measuring things. So with length, the metric measurements are millimetres, centimetres, metres and kilometres. A stamp, would be measured in millimetres.

This metric system had as its fundamental unit of length the meter, defined to be a small fraction of the length of a meridian of the earth. Other units of length were decimal multiples or fractions ...

Units from the metric system can be used to describe the mass, volume or length of an object. Mass is measured in grams (g) and kilograms (kg). Volume is measured in millilitres (ml) and litres (l).